The invention relates to the field of air distribution in building structures and in particular to a plenum chamber with a series of parallel placed louver baffles for the variable intake of fresh and recirculated air. The chamber provides for a more nearly equal dispersement of fresh and recirculated air prior to intake by displacement fans which then disperse a fully mixed air flow to all parts of the building.
The object of the invention is to substantially alleviate the sick building syndrome found in many office buildings today. Recirculate air from inside the building needs to be recirculated with outside air in order to keep it relatively fresh. Fans used today, such as centrifugal fans, found in air distribution systems do some mixing but far less than generally estimated. It is not uncommon where two horizontal air strata of different temperatures enter a double inlet squirrel cage fan the discharge will display three vertical strata, with the two outside of nearly the same temperature and the center strata will be of significantly different temperature. A single inlet fan will display a similar phenomenon.
Air in large buildings must be continually mixed with fresh air from the outside in order to keep it fresh and prevent harmful odors, bacteria, etc. from building up in stagnant air streams. Plenum chambers typically draw from a fresh source of air and recirculated source of air, mix the two streams as thoroughly as possible and then pump the resulting air streams throughout the building. As mentioned above, prior art systems may not adequately mix these two streams. Since one side of the plenum chamber is in connection with one type of air (say fresh) and the other side is in connection with another type (say stale) one side of the outlet duct will contain proportionately more of one type of air than the other type.
As each side of the outlet chamber is connected to various passages leading to rooms in the building, one set of rooms on one side of the building will receive one type of air at the expense of the other. One of these sides recieve primarily recirculated air and this leads to possible illness among the occupants due to contaminant buildup, odors, etc. Hence the term: "sick building syndrome."